In 1929, Pilkington and the Triplex Safety Glass Company formed a joint company to build a plant at Eccleston, St Helens, which initially produced laminated glass. In the 1930s, they entered into a series of agreements for the manufacture and sale in Britain of the newly-developed toughened glass. Pilkington gradually increased its shareholding in Triplex until by 1965 it was the majority shareholder.